close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3076925

код для вставки
Feb. 5, 1963
x. GAL ETAL
CATHODE ASSEMBLY AND METHOD OF‘ MAKING SAME
Filed Dec. 22, 1955
3,076,915
Uite states atent
Free
d?'l??lh
Federated Feb. 5, 1963
2
container and of the porous body overlap one another
3,976,915
CATHODE ASSEM'ELY AND METHGD 9F
MAIGNG SAME
either on one side or on both sides of the edges.
The invention will be explained with greater particu
larity in connection with the accompanying drawing, in
Imre on, Ferenc Nagel, and lEndr-e Qldal, hudapest Hun
gary, assignors to Egyesiiit lzzélarnpa és Villamossag
Részvénytarsasag, Budapest, l- ungary, a Hungarian
enterprise
which:
FIGURE 1 illustrates in vertical section a cathode as—
sembly embodying the invention;
Filed Dec. 22, 1955, Ser. No. 5545,3694
Claims priority, application Hungary Dec. 24, B54
ll} Claims. (Cl. 313-646)
FlGURE 2 is a side elevation and partly a longitudi
nal section of a cathode embodying another modi?cation
of the invention.
This invention relates to cathode assemblies and is con
Referring to FIGURE 1 a ?rst cylindrical container 4 of
cerned in particular with cathodes provided with a reserve
a refractory metal, such as molybdenum, tungsten, tanta
supply of activating material and a covering for the same,
lum or the like is bordered inwardly at its upper end and
said covering being constituted of a refractory porous ma
is closed at this end by means of a refractory porous body
terial.
15 3. We prefer to make the porous body 3 of sintered
This kind of cathodes comprises a chamber containing a
tungsten, but molybdenum, niobium or tantalum may also
supply of the activating material and a second chamber
be used. The edge 8 of the ?rst cylindrical container 4
containing a heating means, the two chambers being sep
is overlapped on both sides by the edges 9 and 10 of the
arated from one another by a partition wall, whereby the
porous body 3.
walls of the chamber containing the activating material 20 Tightly ?tted into the ?rst cylindrical container 4 is a
consist at least partly of a refractory porous material, the
second cylindrical container 6 closed at its upper end 11
pores of said porous material forming the only passages
and located so that the porous body 3, a part of the wall
from within said chamber. During working of the cath
of the cylindrical container 4, and the top 11 of the sec
ode the activating material diffuses through the pores on
ond cylindrical container form a chamber 5 containing
to the outer surface of said porous body forming the
an activating material such as alkaline earth metal com
covering of the chamber containing said activating mate
rial.
Since this kind of cathodes, the so-called reserve supply
cathodes, are generally of very small dimensions, it causes
substantial di?iculties to manufacture the cathode in such 30
a manner that the pores of the refractory porous body
be the only passages from within the chamber containing
the activating material. Di?‘lculties arise also in separat
ing the supply chamber from the chamber containing the
heating means. In order to connect the refractory porous
body with the non porous part of the walls of the supply
chamber and to arrange a partition wall between the
supply chamber and the heating chamber in reserve supply
cathodes suggested or used heretofore, Welded joints had
to be provided. Obviously serious difficulties had to be
overcome resulting from the very small dimensions of
these cathodes having frequently diameters of about
10 mm.
pounds or like materials such as enumerated in the co“
pending application Ser. No. 429,955, now Patent No.
2,902,621. The only passages from within this reservoir
chamber 5 are formed by the pores of the sintered porous
body 3. The vaporizable activating material provided in
the chamber 5 diffuses through the pores of the body 3
and produces upon the outer surface of the body 3 a thin
layer of molecular thicicness of emissive material, as
known in the art. The inner space 12 of the second cylin
35 drical container 6 forms a heating chamber and contains
a heating body, such as a ?lament 7.
The second cylindrical container 6 is at its lower end
supported by an insulating plate 14 made of ceramic
material which again is supported by lead-in wires 15
and 17 of the ?lament 7, passing through the glass stem
18 of the usual envelope 1% of an electric discharge device'
16 is a lead-in to the cathode which may also serve for
additionally ?xing the container 4 to the insulating
plate £4.
One object of the invention is to provide an electrode
which is easier to manufacture than those in use in the 45
The overlapping edges 8, 9 and ill of the ?rst cylindrical
present time, is highly electron cmissive and remains a
container 4 and the porous body 3 form a hermetically
for a long time.
A further obiect of the invention is to provide a cathode
substantially without any welded parts in it and thus es
pecially adapted to wholesale production. Since the cath~
ode according to this invention is assembled Without ap
plication of any heat in the neighborhood of the activat
ing material, this material is not exposed to injuries caused
by heat With cathodes of known construction.
Still another object of the invention is a method of
making an electrode of the kind referred to above for
electric discharge devices.
An accordance with the present invention a cathode
sealed joint so that vapors of the activating material en~
closed in the chamber 5 cannot pass from within the charn~
her but through the pores of the body 3.
The embodiment shown in FlGURE 2 differs from that
of FEGURE 1 only in that the porous body 3 closing the
upper end of the ?rst cylindrical container 4 overlaps the
edge 8 of this container only on its inner side at 13.
According to the preferred method of making the cath
ode described above the cylindrical container 4 bordered
inwardly and made e.g. of molybdenum is put with its
bordered end downwardly into the hollow of a suitable
press mould. After putting a quantity of pulverized
tungsten suthcient to form the body 3 into the container
assembly is provided comprising a ?rst cylindrical con
tainer one end or" which being closed by a refractory 60 4 the powder is pressed under a pressure of about l0~30
tons/cm? into a self-sustaining closing body of the form
porous body, a second cylindrical container closed at
shown in FIGURE 2, whereby the edge 13 of the body 3
one end and tightly ?tted in said ?rst cylindrical con
overlaps the bordered edge 8 of the cylindrical container
tainer, the top parts of said two cylindrical containers en~
4. According to the shape of the tools used for the press
closing a chamber, the pores of said refractory porous
ing operation any other form of the body 3 may be ob
body forming the only passages from within said chamber, 65 tained.
an activating material provided in said chamber and sup
After removing the cylindrical container 4' from the
plying the electron emitting substance through the pores
press mould together with the closing body 3 now forming
of said porous body and heating means provided in the
an integral unit with the container 4», it is heat treated at
inner space of said second cylindrical container. The ?rst
70 a temperature below the melting point of said powdered
cylindrical container closed at one end by said refractory
refractory metal, say of about 1400-1900° C. for about
porous body is bordered inwardly and the edges of the
e.g. ten minutes in a nonoxidizing atmosphere, whereby
3,076,915
a
£9
the body 3 is sintered and forms a unit with the cylindri
cal container 4 made of molybdenum.
In order to form a porous body 3 overlapping the edge
8 of the cylindrical container 4 on both sides as shown
in FIGURE 1 ?rst a small quantity of powdered tungsten
is put in the press mould su?icient to form the upper part
of the body 3, then the bordered cylindrical container 4
is'set with its bordered end down upon said quantity of
powdered tungsten, then again a quantity of powdered
d.
4. A cathode assembly comprising a ?rst container, said
?rst container comprising a non-porous, cylindrical, open
ended ?rst peripheral wall made of a metal selected from
the group consisting of molybdenum, tungsten and tanta
lum, and a transverse disc-like, ?at, porous, refractory end
wall extending closely into one end of said ?rst peripheral
wall, said porous end wall being formed of pressable, sin
terable particles selected from the group consisting of tung
sten, molybdenum, niobium and tantalum, said end wall
tungsten su?‘lcient to form the lower part of the body 3 10 being pressed and sintered in situ and being thereby seal
ingly bonded to said ?rst peripheral wall, said ?rst pe
is put into said ?rst container and then the pressing and
ripheral wall having a transverse, inturned, annular, pe
sintering operations are performed as described above.
After the sintering process has been ?nished the activat
ing material is brought into the cylindrical container 4
which is again turned upside down. The activating ma
terial may be in powdered state or in the form of a pastil
or lozenge. Then the second cylindrical container 6 pref
erably made of the same metal as the ?rst cylindrical con
tainer is pressed into the ?rst cylindrical container 4,
whereby the inner diameter of the container 4 and the
ripheral end ?ange extending into the side of said porous
end Wall with said porous end wall overlapping the re
spective end faces of said ?ange, and a second, non-porous
container comprising a cylindrical second peripheral wall
having a transverse, unitary end wall closure, said second
peripheral wall extending into said ?rst peripheral wall
with said second peripheral wall frictionally slidably abut
ting said ?rst peripheral wall and with said end wall clos
tire of said second container proximate to said porous end
outer diameter of the container 6 are so chosen that after
wall and spaced therefrom to de?ne a chamber therebe
the pressing operation the two containers 4 and 6 ?t
tween, an activating material in said chamber and adapted
tightly into one another and form an integral body. The
when heated to emit vapors which can pass from said
closing body 3 and the top 11 of said second cylindrical
chamber only through the pores of said porous end wall,
container 6 are in a juxtaposed relationship thus forming
and heating means for said activating material mounted
the chamber 5 enclosing said activating material.
in the inner space of said second container.
Instead of ?lling the activating material into the cham
5. The method of making a cathode assembly having a
ber 5 before the second container 6 is pressed into the
reserve supply of activating material enclosed in the cham
?rst container 4, the activating material in the form of a
pastil or lozenge may be ?xed upon the outer surface of 30 ber providing pore-like paths for said activating material,
comprising the ‘steps of compacting pressable, sinterable
the top 11 of the container 6 by means of a suitable bind
particles in one end of the peripheral wall of a non-porous,
ing material such as collodion, and then the container 6
cylindrical, open-ended, container to form a transverse,
pressed into the container 4 together with said activating
disc-like,
?at, porous, refractory end wall extending clos-'
material.
ingly into one end of said container, pressing and'sinter
The heating ?lament 7 which may preferably be coated
ing said end wall particles in situ so as to bond them seal
with aluminum oxide and the insulating support 14 may be
ingly to said ?rst cylindrical container, then locating in
assembled in any known manner. Then the cathode is as
side said ?rst cylindrical container and adjacent its'end
sembled in the container of an electric discharge tube and
wall an activating material which is adapted to emit vapors
activated in any known manner.
Although we have shown and described certain speci?c 40 when heated which pass through the pores of said activat
ing material, and pressing the peripheral wall of a second
embodiments of our invention, we are fully aware that
cylindrical container closed at one end into the peripheral
many modi?cations thereof are possible. Our invention,
wall of said ?rst cylindrical container with saidperipheral
therefore, is not to be restricted, except insofar as is ne
walls frictionally slidably abutting each other and with
cessitated by the prior art.
the closed end of said second cylindrical container proxi
45
What we claim is:
mate to the end wall of said ?rst cylindrical container and
1. A cathode assembly comprising a ?rst container,
spaced therefrom to de?ne the chamberin closing said
said ?rst container comprising a non-porous, cylindrical,
activating material, and providing heating means in the
open-ended ?rst peripheral wall and a transverse disc-like,
inner space of said second cylindrical container.
?at, porous, refractory end wall extending closingly into
6. Method according to claim 5, said method also com
one end of said peripheral wall, said porous end wall be
prising turning said one end of said ?rst container in
ing formed of pressable, sinterable particles, said end wall
wardly to form a transverse ?ange and compacting said
being pressed and sintered in situ and being thereby seal
particles in such a way that said ?ange extends frictional
ingly bonded to said ?rst peripheral wall, and a second,
ly onto said porous end wall.
non-porous container comprising a cylindrical second pe
ripheral wall having a transverse, unitary end wall clos 55 7. Method according to claim 5, said ?rst container be
ing of molybdenum.
ure, said second peripheral wall extending into said ?rst
8. The method of making a cathode assembly having a
peripheral wall with said second peripheral wall friction
reserve supply of activating material enclosed in the cham:
ally slidably abutting said ?rst peripheral wall and with
ber providing pore-like paths for said activating material,
said end wall closure of said second container proximate to
said porous end wall and spaced therefrom to de?ne a 60 comprising the steps of turning inwardly one end of the
peripheral wall of a ?rst cylindrical container to provide a
chamber therebetween, an activating material in said
transverse, annular end ?ange, placing powdered refrac
chamber and adapted when heated to emit vapors which
tory metal into a press mold, setting said ?rst container in
can pass from said chamber only through the pores of said
said press mold with said flange against said powdered re
porous end wall, and heating means for said activating
material mounted in the inner space of said second con 65 fractory metal, placing additional refractory metal into
said ?rst container, pressing said metal particles to form a
tainer.
transverse, disc-like, ?at, porous, refractory end wall ex~
2. A cathode assembly according to claim 1, said ?rst
tending closingly into said end of said container and over
peripheral wall having a transverse, inturned, annular, pe
ripheral ?ange, said ?ange extending frictionally into the
side of said porous end wall. '
3. A cathode assembly according to claim 1, said pe
ripheral Wall having an inturned, transverse, annular, pe
ripheral end ?ange, said ?ange extending frictionally into
the side of said porous end wall and being overlapped on
both end faces thereof by said porous end wall.
lapping the respective end faces of said ?ange, sintering
70 said end wall particles in situ so as to bond them sealingly
to said ?rst cylindrical container, then locating inside said
?rst cylindrical container and adjacent its end wall an ac
tivating material which is adapted to emit vapors when
heated which pass through the pores of said activating ma
75 terial, and pressing the peripheral wall of a second cylin
5
8,076,915
6
drical container closed at one end into the peripheral wall
of said ?rst cylindrical container with said peripheral walls
second cylindrical container, then pressing the peripheral
wall of the second cylindrical container into the peripheral
frictionally slidably abutting each other and with the
wall of said ?rst cylindrical container with said peripheral
closed end of said second cylindrical container proximate
Walls frictionally slidably abutting each other and with the
to the end wall of said ?rst cylindrical container and 5 closed end of said second cylindrical container proximate
spaced therefrom to de?ne the chamber in closing said ac
to the end Wall of said ?rst cylindrical container and
tivating material, and providing heating means in the inner
spaced therefrom to de?ne the chamber enclosing said ac
space of said second cylindrical container.
tivating material, and providing heating means in the
9. Method acording to claim 8, the sintering step being
inner space of said second cylindrical container.
performed at a temperature between 1,400 and l,900° C. 10
10. The method of making a cathode assembly having
References Cited in the ?le of this patent
a reserve supply of activating material enclosed in the
UNITED STATES PATENTS
chamber providing pore-like paths for said activating ma
terial, comprising the steps of compacting pressable, sinter
able particles in one end of the peripheral wall of a non
porous, cylindrical, open-ended container to form a trans
15
verse, disc-like, ?at, porous refractory end Wall extending
closingly into one end of said container, pressing and sin
tering said end wall particles in situ so as to bond them
2,543,728
2,604,603
2,677,873
2,722,626
2,912,611
Lemmens et a1. ______ .._ Feb. 27,
McLinden ___________ __ July 22,
Buck __________________ __ May 11,
Coppola et a1. ______ __,__ Nov. 1,
Beck et a1 ___________ -_.__ Nov. 10,
2,925,514
Lemmens et a1. ____,____ Feb. 16, 1960
sealingly to said ?rst cylindrical container, ?xing an acti 20
vating material upon the outer face of the end wall of a
1951
1952
1954
1955
1959
FOREIGN PATENTS
713,140
Great Britain ________ __ Aug. 4, 1954
Документ
Категория
Без категории
Просмотров
0
Размер файла
505 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа